Shawburn: set variables to unset font-family rules

shawburn/sass/_extra-child-theme.scss

@@ -332,7 +332,8 @@ hr.wp-block-separator.is-style-wide,
 .a8c-posts-list .a8c-posts-list-item__featured span {
 	background: #{map-deep-get($config-global, "color", "background", "light")};
 	color: #{map-deep-get($config-global, "color", "foreground", "light")};
-	font-family: #{map-deep-get($config-global, "font", "family", "ui")};
+	font-family: #{map-deep-get($config-global, "font", "family", "ui")}; // For browsers without CSS custom properties support.
+	font-family: var( --font-base, #{map-deep-get($config-global, "font", "family", "ui")} );
 	//text-transform: uppercase;
 }
 
@@ -343,6 +344,7 @@ hr.wp-block-separator.is-style-wide,
 .jetpack-business-hours {
 	dt {
 		font-family: inherit;
+		font-family: var( --font-base, inherit );
 	}
 }
 

shawburn/style-rtl.css

@@ -3907,6 +3907,7 @@ hr.wp-block-separator.is-style-wide,
 	background: #FAFAFA;
 	color: #767676;
 	font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;
+	font-family: var(--font-base, -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif);
 }
 
 /**
@@ -3914,6 +3915,7 @@ hr.wp-block-separator.is-style-wide,
  */
 .jetpack-business-hours dt {
 	font-family: inherit;
+	font-family: var(--font-base, inherit);
 }
 
 .wp-block-categories .children {

shawburn/style.css

@@ -3936,6 +3936,7 @@ hr.wp-block-separator.is-style-wide,
 	background: #FAFAFA;
 	color: #767676;
 	font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;
+	font-family: var(--font-base, -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif);
 }
 
 /**
@@ -3943,6 +3944,7 @@ hr.wp-block-separator.is-style-wide,
  */
 .jetpack-business-hours dt {
 	font-family: inherit;
+	font-family: var(--font-base, inherit);
 }
 
 .wp-block-categories .children {